1. Field of the Invention
The present invention relates generally to a magnetic head, and more particularly, to a magnetic head for recording and reproducing data in a state in which the magnetic head floats over a rotating recording medium, that is, a rotating magnetic disk, due to an air flow arising between the magnetic head and the magnetic disk.
2. Description of the Related Art
Generally, an ordinary magnetic disk drive that uses a flexible magnetic disk having a coercive force of 900 oersted (Oe) or less as a magnetic recording medium allows a relatively low rotational speed of for example 300 rpm. In this case, magnetic recording and reproduction is performed by causing the magnetic head to be in direct sliding contact with the magnetic disk.
However, with recent advances in high-density recording on magnetic disks, the rotation speed of the magnetic disk has been increased to for example 3000 rpm, with the coercive force of the magnetic disk being increased to 1500 Oe or more. As a result, in order to accommodate such so-called high-capacity magnetic disks a magnetic disk drive has appeared in which the magnetic head is provided with a narrow gap. Hereinafter such a magnetic disk drive will be referred to as a high-capacity magnetic disk drive.
Since a high-capacity magnetic disk drive allows the magnetic disk to be rotated at high speeds, the magnetic disk and the magnetic head used therein may be easily damaged if the magnetic head were to be caused to be in direct contact with the magnetic disk, as is done in the conventional magnetic disk drive.
As a result, the high-capacity magnetic disk drive is designed so that the magnetic head floats in an elevated state over the surface of the high-capacity magnetic disk due to an elevating force arising as a result of an air flow caused by a relative speed between a slider surface of the magnetic head and the magnetic disk. Magnetic recording and reproduction is performed while a state of non-contact between the magnetic head and the magnetic disk is maintained.
FIGS. 1, 2, 3, 4 and 5 show a magnetic head used in the conventional high-capacity magnetic disk drive.
As shown in FIGS. 1 and 2, the conventional high-capacity magnetic head 1 generally comprises a slider 2 and a magnetic head unit 3. The slider 2 supports the magnetic head unit 3 and causes the magnetic head unit 3 to float over the magnetic disk 6.
The top surface of the slider 2 forms an air bearing surface for forming an air bearing with respect to the magnetic disk 6. Additionally, a central groove 2a is formed at a central position of the top surface of the slider 2. As shown in FIG. 1, the central groove 2a divides the air bearing surface into a first air bearing surface 2b located to the right side of the central groove 2a and a second air bearing surface 5 located to the left side.
The magnetic head unit 3 and a pair of grooves or slots 4 are provided at the first air bearing surface 2b. The magnetic head unit 3 for performing magnetic recording and reproducing is formed by sandwiching a gap member between thin plates of magnetic cores.
The slots 4 extend in a tangential direction of the magnetic disk 6, that is, in the direction of arrow X in FIG. 1, and provide a vent for an air flow produced between the magnetic disk 6 and the first air bearing surface 2b. By providing a vent to the air flow produced between the magnetic disk 6 and the first air bearing surface 2b, an elevating force exerted on the magnetic head 1 is reduced. Accordingly, by providing the slots 4, the elevating force of the magnetic head 1 can be controlled.
As described above, the second air bearing surface 5 is formed to the left of the central groove 2a located on the top surface of the slider 2 as shown in FIG. 2. Like the first air bearing surface 2b, the second air bearing surface 5 also produces a force for elevating the magnetic head 1.
FIG. 3 is a lateral cross-sectional view from a radial direction of disk approach. As shown in the drawing, a pair of magnetic heads are supported so as to be opposite each other within the magnetic disk drive. The elevating force generated by the second air bearing surface 5 described above exerts a force that pushes the magnetic disk 6 in the direction of the first air bearing surface 2b, that is, in the direction of the magnetic head unit 3, of the opposite magnetic head 1. Accordingly, the second air bearing surface 5 also functions as a pressure pad for pressing the magnetic disk 6 toward the opposite magnetic head 1.
Additionally, as described above slots 4 are formed in the first air bearing surface 2b. The slots 4 provide a vent for the air flow produced between the magnetic disk 6 and the fist air bearing surface 2b, thus reducing the elevating force exerted on the magnetic head 1. Accordingly, the magnetic disk 6 is deformed by a negative pressure generated in the slots 4 and a pressure generated at the second air bearing surface 5 due to a change in air flow so as to warp toward a gap 3a as the magnetic disk 6 rotates between the pair of magnetic heads 1. With this construction, optimum recording to and reproduction from the magnetic disk 6 is ensured even with floating magnetic heads 1.
A description will now be given of how the magnetic heads 1 face the magnetic disk 6, with reference to FIG. 4 and FIG. 5. FIGS. 4 and 5 show views of a state in which the magnetic head 1 is recording to or reproducing from a magnetic disk 6, from a radial Y direction of the magnetic disk 6.
FIG. 4 shows the magnetic disk 6 in a state of optimal approach to the magnetic head 1.
As shown in FIG. 4, a pair of slots 4 are formed in the first air bearing surface 2b in which the first magnetic head unit 3 is provided. These slots 4 are formed along an entire length of the first air bearing surface, that is, from a leading edge 7 of the magnetic head 1, that is, an edge side of the magnetic head 1 at which the magnetic disk 6 enters the magnetic head 1, to a trailing edge 8 of the magnetic head 1, that is, an edge side of the magnetic head 1 at which the magnetic disk 6 exits the magnetic head 1. As a result, a reduction in the elevating force due to the presence of the slots 4 is generated over the entire extent of the length of the first air bearing surface 2b. 
Accordingly, even in a state of optimal approach a distance H between the magnetic disk 6 and the leading edge 7 of the magnetic head 1 in the above-described construction in which the slots 4 are provided is smaller than a corresponding distance in a construction in which the slots 4 are not provided.
Moreover, with such a construction the magnetic disk 6 is maintained in close proximity to the magnetic head unit 3 as a result of the reduction in elevating force by the slots 4, thus providing optimal magnetic recording and reproduction.
By contrast, FIG. 5 shows a state in which the magnetic disk 6 approaches the magnetic head 1 at a height position lower than that of an optimal approach. Such a small-clearance state of approach results from the flexibility of the magnetic disk 6 or from inevitable errors in the production process thereof. This phenomenon is called penetration.
When the height of the magnetic disk 6 upon approach to the magnetic head 1 is lower than a standard optimum height position as described above, the distance H is reduced to such an extent that the magnetic disk 6 may come into contact with the leading edge 7 of the magnetic head 1, and the magnetic disk 6 or the leading edge 7 of the magnetic head 1 may be damaged as a result.
Additionally, if a structure is used in which no slots 4 are provided in an effort to prevent damage to the magnetic disk 6 due to this penetration, the magnetic disk 6 and the magnetic head unit 3 become separated and it becomes impossible to obtain optimal magnetic recording and reproduction.
Accordingly, it is a general object of the present invention to provide an improved and useful magnetic head in which the disadvantages described above are eliminated. A more specific object of the present invention is to provide a magnetic head capable of preventing damage to the recording medium (magnetic disk) while maintaining a state of optimum magnetic recording and reproduction.
The above-described objects of the present invention are achieved by a magnetic head comprising:
a first magnetic head unit for recording to and reproducing from a first flexible rotating recording medium;
a second magnetic head unit for recording to and reproducing from a second flexible rotating recording medium having a coercive force lower than a coercive force of the first flexible rotating recording medium;
a slider supporting the first magnetic head unit, the slider having a central groove separating a first air bearing surface at which the first magnetic head unit is provided and a second air bearing surface at which the second magnetic head unit is provided, the slider generating an elevating force from an air flow generated in a space between the first and second air bearing surfaces and the flexible rotating recording media;
an elevating force control slot formed on at least the first air bearing surface so as to extend in a direction substantially perpendicular to the direction from which the first or second flexible rotating recording medium approaches the magnetic head; and
an incision formed on a trailing edge side of the slider so as to restrict a width of the first air bearing surface and at the same time penetrate in a direction of the height of the slider,
a distance from a center position of a track of the first magnetic head unit to an edge of the first air bearing surface in the direction from which the first or second flexible rotating recording medium approaches the magnetic head being YH, a distance from a center position of a track of the first magnetic head unit to an edge of the first air bearing surface perpendicular to the direction from which the first or second flexible rotating recording medium approaches the magnetic head being XH, such that 0.01 mmxe2x89xa6YH less than 0.1 mm and 0.01 mmxe2x89xa6XH less than 0.1 mm.
According to the invention described above, the first magnetic head unit can be positioned at a lowest elevation range of the recording medium because the first magnetic head unit and the edge of the first air bearing surface can be positioned near each other. In so doing, it is possible to obtain stable electromagnetic conversion characteristics and at the same time prevent contact between the recording medium and the magnetic head because an ideal floating condition, that is, so-called zero penetration, can be achieved.
Additionally, the above-described objects of the present invention are also achieved by a magnetic head comprising:
a first magnetic head unit for recording to and reproducing from a first flexible rotating recording medium;
a second magnetic head unit for recording to and reproducing from a second flexible rotating recording medium having a coercive force lower than a coercive force of the first flexible rotating recording medium;
a slider supporting the first magnetic head unit, the slider having a central groove separating a first air bearing surface at which the first magnetic head unit is provided and a second air bearing surface at which the second magnetic head unit is provided, the slider generating an elevating force from an air flow generated in a space between the first and second air bearing surfaces and the flexible rotating recording media;
an elevating force control slot formed on at least the first air bearing surface so as to extend in a direction substantially perpendicular to the direction from which the first or second flexible rotating recording medium approaches the magnetic head; and
an incision formed on a trailing edge side of the slider so as to restrict a width of the first air bearing surface and at the same time penetrate in a direction of the height of the slider,
a slanting surface formed on a leading edge side of the first and second air bearing surfaces, respectively, a chamfered portion being formed on an outer periphery of a flat surface portion forming the first and second air bearing surfaces as well as on an outer periphery of a flat surface portion forming the slanting surface.
According to the inventions described above, damage to the recording medium can be reduced.
That is, by forming a curved chamfered portion on an outer periphery of each of the flat surfaces, even when using a recording medium having a tolerance of a penetration of for example approximately xc2x10.2 and this recording medium contacts the magnetic head, because the peripheral portion of each of the flat surfaces that comprise the contact positions has a curved chamfered portion, the surface area of the contact with the recording medium increases and hence the contact load can be dispersed. Accordingly, even if the recording medium contacts the magnetic head, the load per unit of surface area applied to the recording medium is decreased and thus any damage to the recording medium can be reduced.
Additionally, the above-described object of the present invention is also achieved by the magnetic head as described above, wherein of the four corner portions of the flat surfaces forming the first and second air bearing surfaces of the slider at least the two corner portions on the leading edge of the slider have an arc shape of which a radius R is greater than or equal to 0.2 mm but less than or equal to 1 mm.
According to the invention described above, the contact load on a leading edge that is a position at which the recording medium approaches the magnetic head can be dispersed. As a result, even if the leading edge of the magnetic head contacts the recording medium, the load per unit of surface area applied to the recording medium is decreased and thus any damage to the recording medium can be reduced.
Additionally, even if the recording medium contacts the trailing edge, for the same reasons described above damage to the recording medium can be reduced and the recording medium can be more reliably protected.
Additionally, the above-described objects of the present invention is also achieved by the magnetic head as claimed in claim 1, wherein the chamfered is configured so that at least three interference fringes/patterns can be recognized using an optical flat, a pitch S of the interference fringes being such that 10 xcexcmxe2x89xa6Sxe2x89xa650 xcexcm.
According to the invention described above, it is possible to more effectively reduce damage to the above-described recording medium.
Additionally, the above-described object of the present invention is also achieved by a magnetic head comprising:
a first magnetic head unit for recording to and reproducing from a first flexible rotating recording medium;
a second magnetic head unit for recording to and reproducing from a second flexible rotating recording medium having a coercive force lower than a coercive force of the first flexible rotating recording medium;
a slider supporting the first magnetic head unit, the slider having a central groove separating a first air bearing surface at which the first magnetic head unit is provided and a second air bearing surface at which the second magnetic head unit is provided, the slider generating an elevating force from an air flow generated in a space between the first and second air bearing surfaces and the flexible rotating recording media;
an elevating force control slot formed on at least the first air bearing surface so as to extend in a direction substantially perpendicular to the direction from which the first or second flexible rotating recording medium approaches the magnetic head; and
a first incision formed on a trailing edge side of the slider so as to restrict a width of the first air bearing surface and at the same time penetrate in a direction of the height of the slider,
a slanting surface formed on a leading edge of the first and second air bearing surfaces, respectively, a border portion between the slanting surface and the first and second air bearing surfaces forming a continuous curve.
According to the invention described above, it is possible to more effectively reduce damage to the above-described recording medium.
That is, when there is penetration, the position at which the biggest load is most easily applied to the recording medium is the inner sliding side angle of the leading edge toward which the recording medium approaches. This inner sliding side angle corresponds to a position contacting the first and second air bearing surfaces and the slanting surface. This position is the most easily damaged insofar as it is the most easily contacted between the recording medium and the magnetic head.
However, because the border portion between the slanting surface and the first and second air bearing surfaces forms a continuous curve, the surface area of the contact with the recording medium becomes large and hence the contact load can be dispersed. Accordingly, even if the recording medium contacts the magnetic head, the load per unit of surface area applied to the recording medium is decreased and thus any damage to the recording medium can be reduced.
Additionally, the above-described object of the present invention is also achieved by the magnetic head as described above, wherein:
a second incision is formed on a trailing edge of the slider, the trailing edge of the slider being an outer side of the first magnetic head unit; and
a leading edge side of the first air bearing surface having a width A1, a portion near to the first magnetic head unit formed by the second incision having a width A2 smaller than the width A1, a portion distant from the first magnetic head unit not formed by the second incision having a width A3 larger than the width A2 but smaller than the width A1, such that A2xe2x89xa6A3xe2x89xa6A1.
According to the invention described above, the air flow generated between the recording medium and the slider is vented by the second incision, thereby reducing the elevating force in the vicinity of the second incision.
Additionally, the first magnetic head unit can be positioned at a lowest elevation range. In so doing, it is possible to obtain stable electromagnetic conversion characteristics and at the same time prevent contact between the recording medium and the magnetic head because an ideal floating condition, that is, so-called zero penetration, can be achieved.
Additionally, the above-described object of the present invention is also achieved by a magnetic head comprising:
at least one magnetic head unit for recording to and reproducing from a flexible rotating recording medium;
a slider supporting the magnetic head unit, the slider having a central groove separating a first air bearing surface and a second air bearing surface, the slider generating an elevating force from an air flow generated in a space between the first and second air bearing surfaces and the flexible rotating recording media;
an elevating force control slot formed on at least one of either the first or second air bearing surfaces so as to extend in a direction substantially perpendicular to the direction from which the first or second flexible rotating recording medium approaches the magnetic head; and
an incision formed on a trailing edge side of the slider so as to restrict a width of the air bearing surfaces and at the same time penetrate in a direction of the height of the slider,
a distance from a center position of a track of the magnetic head unit to an edge of the air bearing surfaces in the direction from which the flexible rotating recording medium approaches the magnetic head being YH, a distance from a center position of a track of the magnetic head unit to an edge of the air bearing surfaces perpendicular to the direction from which the flexible rotating recording medium approaches the magnetic head being XH, such that 0.01 mmxe2x89xa6YHxe2x89xa60.1 mm and 0.01 mmxe2x89xa6XHxe2x89xa60.1 mm.
According to the invention described above, the magnetic head unit and the edge of the air bearing surface come into close proximity to each other, so the magnetic head unit can be positioned at a lowest elevation range of the recording medium. In so doing, it is possible to obtain stable electromagnetic conversion characteristics and at the same time prevent contact between the recording medium and the magnetic head because an ideal floating condition, that is, so-called zero penetration, can be achieved.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.